Efficient single-longitudinal-mode Nd:YAG laser

A continuous TEM
00
power of more than
\frac{1}{2}
W has been obtained from a single-longitudinal-mode (SLM) Nd:YAG laser pumped with a 1-kW tungsten-iodine lamp. Spatial hole burning, the cause of multilongitudinal mode (MLM) oscillation, was eliminated by placing the rod between two quarter-wave plates. The resulting laser mode had a spatially uniform light intensity along the axis of the laser rod. The linearly polarized SLM power was 78 percent of the polarized MLM output and 62 percent of the total unpolarized TEM
00
power available from the laser. The power reductions were due only to threshold insertion losses. The combination of simplicity and high efficiency has not been found in other SLM techniques for solid ion lasers.